Relation between Intelligibility Scores for Various Test Methods and Different Types of Speech Distortion
Carl E. Williams, Michael H. L. Hecker · The Journal of the Acoustical Society of America · 1966
Several intelligibility tests are currently being used to evaluate speech-communication systems. Individuals engaged in the development of such systems would often like to compare the performance of a system evaluated with one test with the performance of another system that has been evaluated with a different test. A study has been conducted to examine and quantify the relation between scores obtained with four intelligibility tests (the Harvard PB-Word Test, the Fairbanks Rhyme Test, the Modified Rhyme Test, and the Harvard Test Sentences) for various levels of three types of speech distortion (additive speech-shaped noise, peak clipping, and vocoderization). Recordings by two adult male speakers of the different test materials were processed by the three distortion systems, and output recordings were administered to a group of listeners. The results of the study demonstrate that the relation between the various test scores is not unique but depends considerably on the type of speech distortion employed. [Work supported by Decision Sciences Laboratory, Electronic Systems Division, Air Force Systems Command, Bedford, Massachusetts.]